/*
 *	Routines having to do with the 'struct sk_buff' memory handlers.
 *
 *	Authors:	Alan Cox <alan@lxorguk.ukuu.org.uk>
 *			Florian La Roche <rzsfl@rz.uni-sb.de>
 *
 *	Fixes:
 *		Alan Cox	:	Fixed the worst of the load
 *					balancer bugs.
 *		Dave Platt	:	Interrupt stacking fix.
 *	Richard Kooijman	:	Timestamp fixes.
 *		Alan Cox	:	Changed buffer format.
 *		Alan Cox	:	destructor hook for AF_UNIX etc.
 *		Linus Torvalds	:	Better skb_clone.
 *		Alan Cox	:	Added skb_copy.
 *		Alan Cox	:	Added all the changed routines Linus
 *					only put in the headers
 *		Ray VanTassle	:	Fixed --skb->lock in free
 *		Alan Cox	:	skb_copy copy arp field
 *		Andi Kleen	:	slabified it.
 *		Robert Olsson	:	Removed skb_head_pool
 *
 *	NOTE:
 *		The __skb_ routines should be called with interrupts
 *	disabled, or you better be *real* sure that the operation is atomic
 *	with respect to whatever list is being frobbed (e.g. via lock_sock()
 *	or via disabling bottom half handlers, etc).
 *
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License
 *	as published by the Free Software Foundation; either version
 *	2 of the License, or (at your option) any later version.
 */

/*
 *	The functions in this file will not compile correctly with gcc 2.4.x
 */

//#include <linux/module.h>
//#include <linux/types.h>
//#include <linux/kernel.h>
//#include <linux/kmemcheck.h>
//#include <linux/mm.h>
//#include <linux/interrupt.h>
//#include <linux/in.h>
//#include <linux/inet.h>
//#include <linux/slab.h>
//#include <linux/tcp.h>
//#include <linux/udp.h>
//#include <linux/netdevice.h>
//#ifdef CONFIG_NET_CLS_ACT
//#include <net/pkt_sched.h>
//#endif
//#include <linux/string.h>
//#include <linux/skbuff.h>
//#include <linux/splice.h>
//#include <linux/cache.h>
//#include <linux/rtnetlink.h>
//#include <linux/init.h>
//#include <linux/scatterlist.h>
//#include <linux/errqueue.h>
//#include <linux/prefetch.h>

//#include <net/protocol.h>
//#include <net/dst.h>
//#include <net/sock.h>
//#include <net/checksum.h>
//#include <net/xfrm.h>

//#include <asm/uaccess.h>
//#include <asm/system.h>
//#include <trace/events/skb.h>

//#include "kmap_skb.h"

#include "type.h"
#include "skbuff.h"
#include "netdevice.h"

//static struct kmem_cache *skbuff_head_cache __read_mostly;
//static struct kmem_cache *skbuff_fclone_cache __read_mostly;

/*
 *	Keep out-of-line to prevent kernel bloat.
 *	__builtin_return_address is not used because it is not always
 *	reliable.
 */

/**
 *	skb_over_panic	- 	private function
 *	@skb: buffer
 *	@sz: size
 *	@here: address
 *
 *	Out of line support code for skb_put(). Not user callable.
 */
static void skb_over_panic(struct sk_buff *skb, int sz, void *here)
{
	rt_kprintf("skb_over_panic: text:%p len:%d put:%d head:%p "
			  "data:%p tail:%#lx end:%#lx dev:%s\n",
	       here, skb->len, sz, skb->head, skb->data,
	       (unsigned long)skb->tail, (unsigned long)skb->end,
	       skb->dev ? skb->dev->name : "<NULL>");
	RT_ASSERT(0);
}

/**
 *	skb_under_panic	- 	private function
 *	@skb: buffer
 *	@sz: size
 *	@here: address
 *
 *	Out of line support code for skb_push(). Not user callable.
 */

static void skb_under_panic(struct sk_buff *skb, int sz, void *here)
{
	rt_kprintf("skb_under_panic: text:%p len:%d put:%d head:%p "
			  "data:%p tail:%#lx end:%#lx dev:%s\n",
	       here, skb->len, sz, skb->head, skb->data,
	       (unsigned long)skb->tail, (unsigned long)skb->end,
	       skb->dev ? skb->dev->name : "<NULL>");
	RT_ASSERT(0);
}

/* 	Allocate a new skbuff. We do this ourselves so we can fill in a few
 *	'private' fields and also do memory statistics to find all the
 *	[BEEP] leaks.
 *
 */

/**
 *	__alloc_skb	-	allocate a network buffer
 *	@size: size to allocate
 *	@gfp_mask: allocation mask
 *	@fclone: allocate from fclone cache instead of head cache
 *		and allocate a cloned (child) skb
 *	@node: numa node to allocate memory on
 *
 *	Allocate a new &sk_buff. The returned buffer has no headroom and a
 *	tail room of size bytes. The object has a reference count of one.
 *	The return is the buffer. On a failure the return is %NULL.
 *
 *	Buffers may only be allocated from interrupts using a @gfp_mask of
 *	%GFP_ATOMIC.
 */
struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
			    int fclone, int node)
{
//	struct kmem_cache *cache;
	struct skb_shared_info *shinfo;
	struct sk_buff *skb;
	u8 *data;

//	cache = fclone ? skbuff_fclone_cache : skbuff_head_cache;

	/* Get the HEAD */
//	skb = kmem_cache_alloc_node(cache, gfp_mask & ~__GFP_DMA, node);
    skb = kzalloc(sizeof(struct sk_buff), gfp_mask & ~__GFP_DMA);
	if (!skb)
		goto out;
//	prefetchw(skb);

	/* We do our best to align skb_shared_info on a separate cache
	 * line. It usually works because kmalloc(X > SMP_CACHE_BYTES) gives
	 * aligned memory blocks, unless SLUB/SLAB debug is enabled.
	 * Both skb->head and skb_shared_info are cache line aligned.
	 */
	size = SKB_DATA_ALIGN(size);
	size += SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
//	data = kmalloc_node_track_caller(size, gfp_mask, node);
    data = kmalloc(size + sizeof(struct skb_shared_info), gfp_mask);
	if (!data)
		goto nodata;
	/* kmalloc(size) might give us more room than requested.
	 * Put skb_shared_info exactly at the end of allocated zone,
	 * to allow max possible filling before reallocation.
	 */
//	size = SKB_WITH_OVERHEAD(ksize(data));
//	prefetchw(data + size);

	/*
	 * Only clear those fields we need to clear, not those that we will
	 * actually initialise below. Hence, don't put any more fields after
	 * the tail pointer in struct sk_buff!
	 */
	memset(skb, 0, offsetof(struct sk_buff, tail));
	/* Account for allocated memory : skb + skb->head */
	skb->truesize = SKB_TRUESIZE(size);
	atomic_set(&skb->users, 1);
	skb->head = data;
	skb->data = data;
	skb_reset_tail_pointer(skb);
	skb->end = skb->tail + size;
#ifdef NET_SKBUFF_DATA_USES_OFFSET
	skb->mac_header = ~0U;
#endif

	/* make sure we initialize shinfo sequentially */
	shinfo = skb_shinfo(skb);
	memset(shinfo, 0, offsetof(struct skb_shared_info, dataref));
	atomic_set(&shinfo->dataref, 1);
//	kmemcheck_annotate_variable(shinfo->destructor_arg);

	if (fclone) {
		struct sk_buff *child = skb + 1;
		atomic_t *fclone_ref = (atomic_t *) (child + 1);

//		kmemcheck_annotate_bitfield(child, flags1);
//		kmemcheck_annotate_bitfield(child, flags2);
		skb->fclone = SKB_FCLONE_ORIG;
		atomic_set(fclone_ref, 1);

		child->fclone = SKB_FCLONE_UNAVAILABLE;
	}
out:
	return skb;
nodata:
//	kmem_cache_free(cache, skb);
    kfree(skb);
	skb = NULL;
	goto out;
}
//EXPORT_SYMBOL(__alloc_skb);

///**
// *	__netdev_alloc_skb - allocate an skbuff for rx on a specific device
// *	@dev: network device to receive on
// *	@length: length to allocate
// *	@gfp_mask: get_free_pages mask, passed to alloc_skb
// *
// *	Allocate a new &sk_buff and assign it a usage count of one. The
// *	buffer has unspecified headroom built in. Users should allocate
// *	the headroom they think they need without accounting for the
// *	built in space. The built in space is used for optimisations.
// *
// *	%NULL is returned if there is no free memory.
// */
//struct sk_buff *__netdev_alloc_skb(struct net_device *dev,
//		unsigned int length, gfp_t gfp_mask)
//{
//	struct sk_buff *skb;

//	skb = __alloc_skb(length + NET_SKB_PAD, gfp_mask, 0, NUMA_NO_NODE);
//	if (likely(skb)) {
//		skb_reserve(skb, NET_SKB_PAD);
//		skb->dev = dev;
//	}
//	return skb;
//}
//EXPORT_SYMBOL(__netdev_alloc_skb);

//void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page, int off,
//		int size)
//{
//	skb_fill_page_desc(skb, i, page, off, size);
//	skb->len += size;
//	skb->data_len += size;
//	skb->truesize += size;
//}
//EXPORT_SYMBOL(skb_add_rx_frag);

/**
 *	dev_alloc_skb - allocate an skbuff for receiving
 *	@length: length to allocate
 *
 *	Allocate a new &sk_buff and assign it a usage count of one. The
 *	buffer has unspecified headroom built in. Users should allocate
 *	the headroom they think they need without accounting for the
 *	built in space. The built in space is used for optimisations.
 *
 *	%NULL is returned if there is no free memory. Although this function
 *	allocates memory it can be called from an interrupt.
 */
struct sk_buff *dev_alloc_skb(unsigned int length)
{
	/*
	 * There is more code here than it seems:
	 * __dev_alloc_skb is an inline
	 */
	return __dev_alloc_skb(length, GFP_ATOMIC);
}
//EXPORT_SYMBOL(dev_alloc_skb);

static void skb_drop_list(struct sk_buff **listp)
{
	struct sk_buff *list = *listp;

	*listp = NULL;

	do {
		struct sk_buff *this = list;
		list = list->next;
		kfree_skb(this);
	} while (list);
}

static inline void skb_drop_fraglist(struct sk_buff *skb)
{
	skb_drop_list(&skb_shinfo(skb)->frag_list);
}

static void skb_clone_fraglist(struct sk_buff *skb)
{
	struct sk_buff *list;

	skb_walk_frags(skb, list)
		skb_get(list);
}

static void skb_release_data(struct sk_buff *skb)
{
	if (!skb->cloned ||
	    !atomic_sub_return(skb->nohdr ? (1 << SKB_DATAREF_SHIFT) + 1 : 1,
			       &skb_shinfo(skb)->dataref)) {
		if (skb_shinfo(skb)->nr_frags) {
			int i;
			for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
				skb_frag_unref(skb, i);
		}

//		/*
//		 * If skb buf is from userspace, we need to notify the caller
//		 * the lower device DMA has done;
//		 */
//		if (skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY) {
//			struct ubuf_info *uarg;

//			uarg = skb_shinfo(skb)->destructor_arg;
//			if (uarg->callback)
//				uarg->callback(uarg);
//		}

		if (skb_has_frag_list(skb))
			skb_drop_fraglist(skb);

		kfree(skb->head);
	}
}

/*
 *	Free an skbuff by memory without cleaning the state.
 */
static void kfree_skbmem(struct sk_buff *skb)
{
	struct sk_buff *other;
	atomic_t *fclone_ref;

	switch (skb->fclone) {
	case SKB_FCLONE_UNAVAILABLE:
//		kmem_cache_free(skbuff_head_cache, skb);
        kfree(skb);
		break;

	case SKB_FCLONE_ORIG:
		fclone_ref = (atomic_t *) (skb + 2);
		if (atomic_dec_and_test(fclone_ref))
//			kmem_cache_free(skbuff_fclone_cache, skb);
            kfree(skb);
		break;

	case SKB_FCLONE_CLONE:
		fclone_ref = (atomic_t *) (skb + 1);
		other = skb - 1;

		/* The clone portion is available for
		 * fast-cloning again.
		 */
		skb->fclone = SKB_FCLONE_UNAVAILABLE;

		if (atomic_dec_and_test(fclone_ref))
//			kmem_cache_free(skbuff_fclone_cache, other);
            kfree(other);
		break;
	}
}

static void skb_release_head_state(struct sk_buff *skb)
{
//	skb_dst_drop(skb);
#ifdef CONFIG_XFRM
	secpath_put(skb->sp);
#endif
	if (skb->destructor) {
//		WARN_ON(in_irq());
		skb->destructor(skb);
	}
#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
	nf_conntrack_put(skb->nfct);
#endif
#ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
	nf_conntrack_put_reasm(skb->nfct_reasm);
#endif
#ifdef CONFIG_BRIDGE_NETFILTER
	nf_bridge_put(skb->nf_bridge);
#endif
/* XXX: IS this still necessary? - JHS */
#ifdef CONFIG_NET_SCHED
	skb->tc_index = 0;
#ifdef CONFIG_NET_CLS_ACT
	skb->tc_verd = 0;
#endif
#endif
}

/* Free everything but the sk_buff shell. */
static void skb_release_all(struct sk_buff *skb)
{
	skb_release_head_state(skb);
	skb_release_data(skb);
}

///**
// *	__kfree_skb - private function
// *	@skb: buffer
// *
// *	Free an sk_buff. Release anything attached to the buffer.
// *	Clean the state. This is an internal helper function. Users should
// *	always call kfree_skb
// */

void __kfree_skb(struct sk_buff *skb)
{
	skb_release_all(skb);
	kfree_skbmem(skb);
}
//EXPORT_SYMBOL(__kfree_skb);

/**
 *	kfree_skb - free an sk_buff
 *	@skb: buffer to free
 *
 *	Drop a reference to the buffer and free it if the usage count has
 *	hit zero.
 */
void kfree_skb(struct sk_buff *skb)
{
	if (unlikely(!skb))
		return;
	/*if (likely(atomic_read(&skb->users) == 1))
		smp_rmb();
	else */if (likely(!atomic_dec_and_test(&skb->users)))
		return;
//	trace_kfree_skb(skb, __builtin_return_address(0));
	__kfree_skb(skb);
}
//EXPORT_SYMBOL(kfree_skb);

/**
 *	consume_skb - free an skbuff
 *	@skb: buffer to free
 *
 *	Drop a ref to the buffer and free it if the usage count has hit zero
 *	Functions identically to kfree_skb, but kfree_skb assumes that the frame
 *	is being dropped after a failure and notes that
 */
void consume_skb(struct sk_buff *skb)
{
	if (unlikely(!skb))
		return;
	/*if (likely(atomic_read(&skb->users) == 1))
		smp_rmb();
	else */if (likely(!atomic_dec_and_test(&skb->users)))
		return;
//	trace_consume_skb(skb);
	__kfree_skb(skb);
}
//EXPORT_SYMBOL(consume_skb);

///**
// * 	skb_recycle - clean up an skb for reuse
// * 	@skb: buffer
// *
// * 	Recycles the skb to be reused as a receive buffer. This
// * 	function does any necessary reference count dropping, and
// * 	cleans up the skbuff as if it just came from __alloc_skb().
// */
//void skb_recycle(struct sk_buff *skb)
//{
//	struct skb_shared_info *shinfo;

//	skb_release_head_state(skb);

//	shinfo = skb_shinfo(skb);
//	memset(shinfo, 0, offsetof(struct skb_shared_info, dataref));
//	atomic_set(&shinfo->dataref, 1);

//	memset(skb, 0, offsetof(struct sk_buff, tail));
//	skb->data = skb->head + NET_SKB_PAD;
//	skb_reset_tail_pointer(skb);
//}
//EXPORT_SYMBOL(skb_recycle);

///**
// *	skb_recycle_check - check if skb can be reused for receive
// *	@skb: buffer
// *	@skb_size: minimum receive buffer size
// *
// *	Checks that the skb passed in is not shared or cloned, and
// *	that it is linear and its head portion at least as large as
// *	skb_size so that it can be recycled as a receive buffer.
// *	If these conditions are met, this function does any necessary
// *	reference count dropping and cleans up the skbuff as if it
// *	just came from __alloc_skb().
// */
//bool skb_recycle_check(struct sk_buff *skb, int skb_size)
//{
//	if (!skb_is_recycleable(skb, skb_size))
//		return false;

//	skb_recycle(skb);

//	return true;
//}
//EXPORT_SYMBOL(skb_recycle_check);

static inline void skb_dst_copy(struct sk_buff *nskb, const struct sk_buff *oskb)
{
	nskb->_skb_refdst = oskb->_skb_refdst;
//	if (!(nskb->_skb_refdst & SKB_DST_NOREF))
//		dst_clone(skb_dst(nskb));
}

static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
{
	new->tstamp		= old->tstamp;
	new->dev		= old->dev;
	new->transport_header	= old->transport_header;
	new->network_header	= old->network_header;
	new->mac_header		= old->mac_header;
	skb_dst_copy(new, old);
	new->rxhash		= old->rxhash;
	new->ooo_okay		= old->ooo_okay;
	new->l4_rxhash		= old->l4_rxhash;
#ifdef CONFIG_XFRM
	new->sp			= secpath_get(old->sp);
#endif
	memcpy(new->cb, old->cb, sizeof(old->cb));
	new->csum		= old->csum;
	new->local_df		= old->local_df;
	new->pkt_type		= old->pkt_type;
	new->ip_summed		= old->ip_summed;
	skb_copy_queue_mapping(new, old);
	new->priority		= old->priority;
#if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE)
	new->ipvs_property	= old->ipvs_property;
#endif
	new->protocol		= old->protocol;
	new->mark		= old->mark;
	new->skb_iif		= old->skb_iif;
	__nf_copy(new, old);
#if defined(CONFIG_NETFILTER_XT_TARGET_TRACE) || \
    defined(CONFIG_NETFILTER_XT_TARGET_TRACE_MODULE)
	new->nf_trace		= old->nf_trace;
#endif
#ifdef CONFIG_NET_SCHED
	new->tc_index		= old->tc_index;
#ifdef CONFIG_NET_CLS_ACT
	new->tc_verd		= old->tc_verd;
#endif
#endif
	new->vlan_tci		= old->vlan_tci;

	skb_copy_secmark(new, old);
}

/*
 * You should not add any new code to this function.  Add it to
 * __copy_skb_header above instead.
 */
static struct sk_buff *__skb_clone(struct sk_buff *n, struct sk_buff *skb)
{
#define C(x) n->x = skb->x

	n->next = n->prev = NULL;
//	n->sk = NULL;
	__copy_skb_header(n, skb);

	C(len);
	C(data_len);
	C(mac_len);
	n->hdr_len = skb->nohdr ? skb_headroom(skb) : skb->hdr_len;
	n->cloned = 1;
	n->nohdr = 0;
	n->destructor = NULL;
	C(tail);
	C(end);
	C(head);
	C(data);
	C(truesize);
	atomic_set(&n->users, 1);

	atomic_inc(&(skb_shinfo(skb)->dataref));
	skb->cloned = 1;

	return n;
#undef C
}

///**
// *	skb_morph	-	morph one skb into another
// *	@dst: the skb to receive the contents
// *	@src: the skb to supply the contents
// *
// *	This is identical to skb_clone except that the target skb is
// *	supplied by the user.
// *
// *	The target skb is returned upon exit.
// */
//struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src)
//{
//	skb_release_all(dst);
//	return __skb_clone(dst, src);
//}
////EXPORT_SYMBOL_GPL(skb_morph);

///*	skb_copy_ubufs	-	copy userspace skb frags buffers to kernel
// *	@skb: the skb to modify
// *	@gfp_mask: allocation priority
// *
// *	This must be called on SKBTX_DEV_ZEROCOPY skb.
// *	It will copy all frags into kernel and drop the reference
// *	to userspace pages.
// *
// *	If this function is called from an interrupt gfp_mask() must be
// *	%GFP_ATOMIC.
// *
// *	Returns 0 on success or a negative error code on failure
// *	to allocate kernel memory to copy to.
// */
//int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask)
//{
//	int i;
//	int num_frags = skb_shinfo(skb)->nr_frags;
//	struct page *page, *head = NULL;
//	struct ubuf_info *uarg = skb_shinfo(skb)->destructor_arg;

//	for (i = 0; i < num_frags; i++) {
//		u8 *vaddr;
//		skb_frag_t *f = &skb_shinfo(skb)->frags[i];

//		page = alloc_page(GFP_ATOMIC);
//		if (!page) {
//			while (head) {
//				struct page *next = (struct page *)head->private;
//				put_page(head);
//				head = next;
//			}
//			return -ENOMEM;
//		}
//		vaddr = kmap_skb_frag(&skb_shinfo(skb)->frags[i]);
//		memcpy(page_address(page),
//		       vaddr + f->page_offset, skb_frag_size(f));
//		kunmap_skb_frag(vaddr);
//		page->private = (unsigned long)head;
//		head = page;
//	}

//	/* skb frags release userspace buffers */
//	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
//		skb_frag_unref(skb, i);

//	uarg->callback(uarg);

//	/* skb frags point to kernel buffers */
//	for (i = skb_shinfo(skb)->nr_frags; i > 0; i--) {
//		__skb_fill_page_desc(skb, i-1, head, 0,
//				     skb_shinfo(skb)->frags[i - 1].size);
//		head = (struct page *)head->private;
//	}

//	skb_shinfo(skb)->tx_flags &= ~SKBTX_DEV_ZEROCOPY;
//	return 0;
//}
////EXPORT_SYMBOL_GPL(skb_copy_ubufs);

/**
 *	skb_clone	-	duplicate an sk_buff
 *	@skb: buffer to clone
 *	@gfp_mask: allocation priority
 *
 *	Duplicate an &sk_buff. The new one is not owned by a socket. Both
 *	copies share the same packet data but not structure. The new
 *	buffer has a reference count of 1. If the allocation fails the
 *	function returns %NULL otherwise the new buffer is returned.
 *
 *	If this function is called from an interrupt gfp_mask() must be
 *	%GFP_ATOMIC.
 */

struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t gfp_mask)
{
	struct sk_buff *n;

//	if (skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY) {
//		if (skb_copy_ubufs(skb, gfp_mask))
//			return NULL;
//	}

	n = skb + 1;
	if (skb->fclone == SKB_FCLONE_ORIG &&
	    n->fclone == SKB_FCLONE_UNAVAILABLE) {
		atomic_t *fclone_ref = (atomic_t *) (n + 1);
		n->fclone = SKB_FCLONE_CLONE;
		atomic_inc(fclone_ref);
	} else {
//		n = kmem_cache_alloc(skbuff_head_cache, gfp_mask);
        n = kzalloc(sizeof(struct sk_buff), gfp_mask);
		if (!n)
			return NULL;

//		kmemcheck_annotate_bitfield(n, flags1);
//		kmemcheck_annotate_bitfield(n, flags2);
		n->fclone = SKB_FCLONE_UNAVAILABLE;
	}

	return __skb_clone(n, skb);
}
//EXPORT_SYMBOL(skb_clone);

static void copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
{
#ifndef NET_SKBUFF_DATA_USES_OFFSET
	/*
	 *	Shift between the two data areas in bytes
	 */
	unsigned long offset = new->data - old->data;
#endif

	__copy_skb_header(new, old);

#ifndef NET_SKBUFF_DATA_USES_OFFSET
	/* {transport,network,mac}_header are relative to skb->head */
	new->transport_header += offset;
	new->network_header   += offset;
	if (skb_mac_header_was_set(new))
		new->mac_header	      += offset;
#endif
	skb_shinfo(new)->gso_size = skb_shinfo(old)->gso_size;
	skb_shinfo(new)->gso_segs = skb_shinfo(old)->gso_segs;
	skb_shinfo(new)->gso_type = skb_shinfo(old)->gso_type;
}

///**
// *	skb_copy	-	create private copy of an sk_buff
// *	@skb: buffer to copy
// *	@gfp_mask: allocation priority
// *
// *	Make a copy of both an &sk_buff and its data. This is used when the
// *	caller wishes to modify the data and needs a private copy of the
// *	data to alter. Returns %NULL on failure or the pointer to the buffer
// *	on success. The returned buffer has a reference count of 1.
// *
// *	As by-product this function converts non-linear &sk_buff to linear
// *	one, so that &sk_buff becomes completely private and caller is allowed
// *	to modify all the data of returned buffer. This means that this
// *	function is not recommended for use in circumstances when only
// *	header is going to be modified. Use pskb_copy() instead.
// */

//struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t gfp_mask)
//{
//	int headerlen = skb_headroom(skb);
//	unsigned int size = skb_end_offset(skb) + skb->data_len;
//	struct sk_buff *n = alloc_skb(size, gfp_mask);

//	if (!n)
//		return NULL;

//	/* Set the data pointer */
//	skb_reserve(n, headerlen);
//	/* Set the tail pointer and length */
//	skb_put(n, skb->len);

//	if (skb_copy_bits(skb, -headerlen, n->head, headerlen + skb->len))
//		BUG();

//	copy_skb_header(n, skb);
//	return n;
//}
//EXPORT_SYMBOL(skb_copy);

/**
 *	pskb_copy	-	create copy of an sk_buff with private head.
 *	@skb: buffer to copy
 *	@gfp_mask: allocation priority
 *
 *	Make a copy of both an &sk_buff and part of its data, located
 *	in header. Fragmented data remain shared. This is used when
 *	the caller wishes to modify only header of &sk_buff and needs
 *	private copy of the header to alter. Returns %NULL on failure
 *	or the pointer to the buffer on success.
 *	The returned buffer has a reference count of 1.
 */

struct sk_buff *pskb_copy(struct sk_buff *skb, gfp_t gfp_mask)
{
	unsigned int size = skb_end_pointer(skb) - skb->head;
	struct sk_buff *n = alloc_skb(size, gfp_mask);

	if (!n)
		goto out;

	/* Set the data pointer */
	skb_reserve(n, skb_headroom(skb));
	/* Set the tail pointer and length */
	skb_put(n, skb_headlen(skb));
	/* Copy the bytes */
	skb_copy_from_linear_data(skb, n->data, n->len);

	n->truesize += skb->data_len;
	n->data_len  = skb->data_len;
	n->len	     = skb->len;

	if (skb_shinfo(skb)->nr_frags) {
		int i;

//		if (skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY) {
//			if (skb_copy_ubufs(skb, gfp_mask)) {
//				kfree_skb(n);
//				n = NULL;
//				goto out;
//			}
//		}
		for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
			skb_shinfo(n)->frags[i] = skb_shinfo(skb)->frags[i];
			skb_frag_ref(skb, i);
		}
		skb_shinfo(n)->nr_frags = i;
	}

	if (skb_has_frag_list(skb)) {
		skb_shinfo(n)->frag_list = skb_shinfo(skb)->frag_list;
		skb_clone_fraglist(n);
	}

	copy_skb_header(n, skb);
out:
	return n;
}
//EXPORT_SYMBOL(pskb_copy);

/**
 *	pskb_expand_head - reallocate header of &sk_buff
 *	@skb: buffer to reallocate
 *	@nhead: room to add at head
 *	@ntail: room to add at tail
 *	@gfp_mask: allocation priority
 *
 *	Expands (or creates identical copy, if &nhead and &ntail are zero)
 *	header of skb. &sk_buff itself is not changed. &sk_buff MUST have
 *	reference count of 1. Returns zero in the case of success or error,
 *	if expansion failed. In the last case, &sk_buff is not changed.
 *
 *	All the pointers pointing into skb header may change and must be
 *	reloaded after call to this function.
 */

int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail,
		     gfp_t gfp_mask)
{
	int i;
	u8 *data;
	int size = nhead + skb_end_offset(skb) + ntail;
	long off;
	bool fastpath;

	RT_ASSERT(nhead >= 0);

	if (skb_shared(skb))
		RT_ASSERT(0);

	size = SKB_DATA_ALIGN(size);

	/* Check if we can avoid taking references on fragments if we own
	 * the last reference on skb->head. (see skb_release_data())
	 */
	if (!skb->cloned)
		fastpath = true;
	else {
		int delta = skb->nohdr ? (1 << SKB_DATAREF_SHIFT) + 1 : 1;
		fastpath = atomic_read(&skb_shinfo(skb)->dataref) == delta;
	}

//	if (fastpath &&
//	    size + sizeof(struct skb_shared_info) <= ksize(skb->head)) {
//		memmove(skb->head + size, skb_shinfo(skb),
//			offsetof(struct skb_shared_info,
//				 frags[skb_shinfo(skb)->nr_frags]));
//		memmove(skb->head + nhead, skb->head,
//			skb_tail_pointer(skb) - skb->head);
//		off = nhead;
//		goto adjust_others;
//	}

	data = kmalloc(size + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)),
		       gfp_mask);
	if (!data)
		goto nodata;
//	size = SKB_WITH_OVERHEAD(ksize(data));

	/* Copy only real data... and, alas, header. This should be
	 * optimized for the cases when header is void.
	 */
	memcpy(data + nhead, skb->head, skb_tail_pointer(skb) - skb->head);

	memcpy((struct skb_shared_info *)(data + size),
	       skb_shinfo(skb),
	       offsetof(struct skb_shared_info, frags[skb_shinfo(skb)->nr_frags]));

	if (fastpath) {
		kfree(skb->head);
	} else {
		/* copy this zero copy skb frags */
		if (skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY) {
			if (0/*skb_copy_ubufs(skb, gfp_mask)*/)
				goto nofrags;
		}
		for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
			skb_frag_ref(skb, i);

		if (skb_has_frag_list(skb))
			skb_clone_fraglist(skb);

		skb_release_data(skb);
	}
	off = (data + nhead) - skb->head;

	skb->head     = data;
//adjust_others:
	skb->data    += off;
#ifdef NET_SKBUFF_DATA_USES_OFFSET
	skb->end      = size;
	off           = nhead;
#else
	skb->end      = skb->head + size;
#endif
	/* {transport,network,mac}_header and tail are relative to skb->head */
	skb->tail	      += off;
	skb->transport_header += off;
	skb->network_header   += off;
	if (skb_mac_header_was_set(skb))
		skb->mac_header += off;
	/* Only adjust this if it actually is csum_start rather than csum */
	if (skb->ip_summed == CHECKSUM_PARTIAL)
		skb->csum_start += nhead;
	skb->cloned   = 0;
	skb->hdr_len  = 0;
	skb->nohdr    = 0;
	atomic_set(&skb_shinfo(skb)->dataref, 1);
	return 0;

nofrags:
	kfree(data);
nodata:
	return -ENOMEM;
}
//EXPORT_SYMBOL(pskb_expand_head);

///* Make private copy of skb with writable head and some headroom */

struct sk_buff *skb_realloc_headroom(struct sk_buff *skb, unsigned int headroom)
{
	struct sk_buff *skb2;
	int delta = headroom - skb_headroom(skb);

	if (delta <= 0)
		skb2 = pskb_copy(skb, GFP_ATOMIC);
	else {
		skb2 = skb_clone(skb, GFP_ATOMIC);
		if (skb2 && pskb_expand_head(skb2, SKB_DATA_ALIGN(delta), 0,
					     GFP_ATOMIC)) {
			kfree_skb(skb2);
			skb2 = NULL;
		}
	}
	return skb2;
}
//EXPORT_SYMBOL(skb_realloc_headroom);

///**
// *	skb_copy_expand	-	copy and expand sk_buff
// *	@skb: buffer to copy
// *	@newheadroom: new free bytes at head
// *	@newtailroom: new free bytes at tail
// *	@gfp_mask: allocation priority
// *
// *	Make a copy of both an &sk_buff and its data and while doing so
// *	allocate additional space.
// *
// *	This is used when the caller wishes to modify the data and needs a
// *	private copy of the data to alter as well as more space for new fields.
// *	Returns %NULL on failure or the pointer to the buffer
// *	on success. The returned buffer has a reference count of 1.
// *
// *	You must pass %GFP_ATOMIC as the allocation priority if this function
// *	is called from an interrupt.
// */
//struct sk_buff *skb_copy_expand(const struct sk_buff *skb,
//				int newheadroom, int newtailroom,
//				gfp_t gfp_mask)
//{
//	/*
//	 *	Allocate the copy buffer
//	 */
//	struct sk_buff *n = alloc_skb(newheadroom + skb->len + newtailroom,
//				      gfp_mask);
//	int oldheadroom = skb_headroom(skb);
//	int head_copy_len, head_copy_off;
//	int off;

//	if (!n)
//		return NULL;

//	skb_reserve(n, newheadroom);

//	/* Set the tail pointer and length */
//	skb_put(n, skb->len);

//	head_copy_len = oldheadroom;
//	head_copy_off = 0;
//	if (newheadroom <= head_copy_len)
//		head_copy_len = newheadroom;
//	else
//		head_copy_off = newheadroom - head_copy_len;

//	/* Copy the linear header and data. */
//	if (skb_copy_bits(skb, -head_copy_len, n->head + head_copy_off,
//			  skb->len + head_copy_len))
//		BUG();

//	copy_skb_header(n, skb);

//	off                  = newheadroom - oldheadroom;
//	if (n->ip_summed == CHECKSUM_PARTIAL)
//		n->csum_start += off;
//#ifdef NET_SKBUFF_DATA_USES_OFFSET
//	n->transport_header += off;
//	n->network_header   += off;
//	if (skb_mac_header_was_set(skb))
//		n->mac_header += off;
//#endif

//	return n;
//}
//EXPORT_SYMBOL(skb_copy_expand);

///**
// *	skb_pad			-	zero pad the tail of an skb
// *	@skb: buffer to pad
// *	@pad: space to pad
// *
// *	Ensure that a buffer is followed by a padding area that is zero
// *	filled. Used by network drivers which may DMA or transfer data
// *	beyond the buffer end onto the wire.
// *
// *	May return error in out of memory cases. The skb is freed on error.
// */

//int skb_pad(struct sk_buff *skb, int pad)
//{
//	int err;
//	int ntail;

//	/* If the skbuff is non linear tailroom is always zero.. */
//	if (!skb_cloned(skb) && skb_tailroom(skb) >= pad) {
//		memset(skb->data+skb->len, 0, pad);
//		return 0;
//	}

//	ntail = skb->data_len + pad - (skb->end - skb->tail);
//	if (likely(skb_cloned(skb) || ntail > 0)) {
//		err = pskb_expand_head(skb, 0, ntail, GFP_ATOMIC);
//		if (unlikely(err))
//			goto free_skb;
//	}

//	/* FIXME: The use of this function with non-linear skb's really needs
//	 * to be audited.
//	 */
//	err = skb_linearize(skb);
//	if (unlikely(err))
//		goto free_skb;

//	memset(skb->data + skb->len, 0, pad);
//	return 0;

//free_skb:
//	kfree_skb(skb);
//	return err;
//}
//EXPORT_SYMBOL(skb_pad);

/**
 *	skb_put - add data to a buffer
 *	@skb: buffer to use
 *	@len: amount of data to add
 *
 *	This function extends the used data area of the buffer. If this would
 *	exceed the total buffer size the kernel will panic. A pointer to the
 *	first byte of the extra data is returned.
 */
unsigned char *skb_put(struct sk_buff *skb, unsigned int len)
{
	unsigned char *tmp = skb_tail_pointer(skb);
	SKB_LINEAR_ASSERT(skb);
	skb->tail += len;
	skb->len  += len;
	if (unlikely(skb->tail > skb->end))
		skb_over_panic(skb, len, __builtin_return_address(0));
	return tmp;
}
//EXPORT_SYMBOL(skb_put);

/**
 *	skb_push - add data to the start of a buffer
 *	@skb: buffer to use
 *	@len: amount of data to add
 *
 *	This function extends the used data area of the buffer at the buffer
 *	start. If this would exceed the total buffer headroom the kernel will
 *	panic. A pointer to the first byte of the extra data is returned.
 */
unsigned char *skb_push(struct sk_buff *skb, unsigned int len)
{
	skb->data -= len;
	skb->len  += len;
	if (unlikely(skb->data<skb->head))
		skb_under_panic(skb, len, __builtin_return_address(0));
	return skb->data;
}
//EXPORT_SYMBOL(skb_push);

/**
 *	skb_pull - remove data from the start of a buffer
 *	@skb: buffer to use
 *	@len: amount of data to remove
 *
 *	This function removes data from the start of a buffer, returning
 *	the memory to the headroom. A pointer to the next data in the buffer
 *	is returned. Once the data has been pulled future pushes will overwrite
 *	the old data.
 */
unsigned char *skb_pull(struct sk_buff *skb, unsigned int len)
{
	return skb_pull_inline(skb, len);
}
//EXPORT_SYMBOL(skb_pull);

/**
 *	skb_trim - remove end from a buffer
 *	@skb: buffer to alter
 *	@len: new length
 *
 *	Cut the length of a buffer down by removing data from the tail. If
 *	the buffer is already under the length specified it is not modified.
 *	The skb must be linear.
 */
void skb_trim(struct sk_buff *skb, unsigned int len)
{
	if (skb->len > len)
		__skb_trim(skb, len);
}
//EXPORT_SYMBOL(skb_trim);

///* Trims skb to length len. It can change skb pointers.
// */

//int ___pskb_trim(struct sk_buff *skb, unsigned int len)
//{
//	struct sk_buff **fragp;
//	struct sk_buff *frag;
//	int offset = skb_headlen(skb);
//	int nfrags = skb_shinfo(skb)->nr_frags;
//	int i;
//	int err;

//	if (skb_cloned(skb) &&
//	    unlikely((err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC))))
//		return err;

//	i = 0;
//	if (offset >= len)
//		goto drop_pages;

//	for (; i < nfrags; i++) {
//		int end = offset + skb_frag_size(&skb_shinfo(skb)->frags[i]);

//		if (end < len) {
//			offset = end;
//			continue;
//		}

//		skb_frag_size_set(&skb_shinfo(skb)->frags[i++], len - offset);

//drop_pages:
//		skb_shinfo(skb)->nr_frags = i;

//		for (; i < nfrags; i++)
//			skb_frag_unref(skb, i);

//		if (skb_has_frag_list(skb))
//			skb_drop_fraglist(skb);
//		goto done;
//	}

//	for (fragp = &skb_shinfo(skb)->frag_list; (frag = *fragp);
//	     fragp = &frag->next) {
//		int end = offset + frag->len;

//		if (skb_shared(frag)) {
//			struct sk_buff *nfrag;

//			nfrag = skb_clone(frag, GFP_ATOMIC);
//			if (unlikely(!nfrag))
//				return -ENOMEM;

//			nfrag->next = frag->next;
//			kfree_skb(frag);
//			frag = nfrag;
//			*fragp = frag;
//		}

//		if (end < len) {
//			offset = end;
//			continue;
//		}

//		if (end > len &&
//		    unlikely((err = pskb_trim(frag, len - offset))))
//			return err;

//		if (frag->next)
//			skb_drop_list(&frag->next);
//		break;
//	}

//done:
//	if (len > skb_headlen(skb)) {
//		skb->data_len -= skb->len - len;
//		skb->len       = len;
//	} else {
//		skb->len       = len;
//		skb->data_len  = 0;
//		skb_set_tail_pointer(skb, len);
//	}

//	return 0;
//}
//EXPORT_SYMBOL(___pskb_trim);

///**
// *	__pskb_pull_tail - advance tail of skb header
// *	@skb: buffer to reallocate
// *	@delta: number of bytes to advance tail
// *
// *	The function makes a sense only on a fragmented &sk_buff,
// *	it expands header moving its tail forward and copying necessary
// *	data from fragmented part.
// *
// *	&sk_buff MUST have reference count of 1.
// *
// *	Returns %NULL (and &sk_buff does not change) if pull failed
// *	or value of new tail of skb in the case of success.
// *
// *	All the pointers pointing into skb header may change and must be
// *	reloaded after call to this function.
// */

/* Moves tail of skb head forward, copying data from fragmented part,
 * when it is necessary.
 * 1. It may fail due to malloc failure.
 * 2. It may change skb pointers.
 *
 * It is pretty complicated. Luckily, it is called only in exceptional cases.
 */
unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta)
{
	/* If skb has not enough free space at tail, get new one
	 * plus 128 bytes for future expansions. If we have enough
	 * room at tail, reallocate without expansion only if skb is cloned.
	 */
	int i, k, eat = (skb->tail + delta) - skb->end;

	if (eat > 0 || skb_cloned(skb)) {
		if (pskb_expand_head(skb, 0, eat > 0 ? eat + 128 : 0,
				     GFP_ATOMIC))
			return NULL;
	}

	if (skb_copy_bits(skb, skb_headlen(skb), skb_tail_pointer(skb), delta))
		RT_ASSERT(0);

	/* Optimization: no fragments, no reasons to preestimate
	 * size of pulled pages. Superb.
	 */
	if (!skb_has_frag_list(skb))
		goto pull_pages;

	/* Estimate size of pulled pages. */
	eat = delta;
	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
		int size = skb_frag_size(&skb_shinfo(skb)->frags[i]);

		if (size >= eat)
			goto pull_pages;
		eat -= size;
	}

	/* If we need update frag list, we are in troubles.
	 * Certainly, it possible to add an offset to skb data,
	 * but taking into account that pulling is expected to
	 * be very rare operation, it is worth to fight against
	 * further bloating skb head and crucify ourselves here instead.
	 * Pure masohism, indeed. 8)8)
	 */
	if (eat) {
		struct sk_buff *list = skb_shinfo(skb)->frag_list;
		struct sk_buff *clone = NULL;
		struct sk_buff *insp = NULL;

		do {
			RT_ASSERT(list);

			if (list->len <= eat) {
				/* Eaten as whole. */
				eat -= list->len;
				list = list->next;
				insp = list;
			} else {
				/* Eaten partially. */

				if (skb_shared(list)) {
					/* Sucks! We need to fork list. :-( */
					clone = skb_clone(list, GFP_ATOMIC);
					if (!clone)
						return NULL;
					insp = list->next;
					list = clone;
				} else {
					/* This may be pulled without
					 * problems. */
					insp = list;
				}
				if (!pskb_pull(list, eat)) {
					kfree_skb(clone);
					return NULL;
				}
				break;
			}
		} while (eat);

		/* Free pulled out fragments. */
		while ((list = skb_shinfo(skb)->frag_list) != insp) {
			skb_shinfo(skb)->frag_list = list->next;
			kfree_skb(list);
		}
		/* And insert new clone at head. */
		if (clone) {
			clone->next = list;
			skb_shinfo(skb)->frag_list = clone;
		}
	}
	/* Success! Now we may commit changes to skb data. */

pull_pages:
	eat = delta;
	k = 0;
	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
		int size = skb_frag_size(&skb_shinfo(skb)->frags[i]);

		if (size <= eat) {
			skb_frag_unref(skb, i);
			eat -= size;
		} else {
			skb_shinfo(skb)->frags[k] = skb_shinfo(skb)->frags[i];
			if (eat) {
				skb_shinfo(skb)->frags[k].page_offset += eat;
				skb_frag_size_sub(&skb_shinfo(skb)->frags[k], eat);
				eat = 0;
			}
			k++;
		}
	}
	skb_shinfo(skb)->nr_frags = k;

	skb->tail     += delta;
	skb->data_len -= delta;

	return skb_tail_pointer(skb);
}
//EXPORT_SYMBOL(__pskb_pull_tail);

/**
 *	skb_copy_bits - copy bits from skb to kernel buffer
 *	@skb: source skb
 *	@offset: offset in source
 *	@to: destination buffer
 *	@len: number of bytes to copy
 *
 *	Copy the specified number of bytes from the source skb to the
 *	destination buffer.
 *
 *	CAUTION ! :
 *		If its prototype is ever changed,
 *		check arch/{*}/net/{*}.S files,
 *		since it is called from BPF assembly code.
 */
int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len)
{
	int start = skb_headlen(skb);
	struct sk_buff *frag_iter;
	int i, copy;

	if (offset > (int)skb->len - len)
		goto fault;

	/* Copy header. */
	if ((copy = start - offset) > 0) {
		if (copy > len)
			copy = len;
		skb_copy_from_linear_data_offset(skb, offset, to, copy);
		if ((len -= copy) == 0)
			return 0;
		offset += copy;
		to = (u8 *)to + copy;//to     += copy;
	}

	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
		int end;

//		WARN_ON(start > offset + len);

		end = start + skb_frag_size(&skb_shinfo(skb)->frags[i]);
		if ((copy = end - offset) > 0) {
			u8 *vaddr;

			if (copy > len)
				copy = len;

//			vaddr = kmap_skb_frag(&skb_shinfo(skb)->frags[i]);
            vaddr = (u8 *)&skb_shinfo(skb)->frags[i];
			memcpy(to,
			       vaddr + skb_shinfo(skb)->frags[i].page_offset+
			       offset - start, copy);
//			kunmap_skb_frag(vaddr);

			if ((len -= copy) == 0)
				return 0;
			offset += copy;
			to = (u8 *)to + copy;//to     += copy;
		}
		start = end;
	}

	skb_walk_frags(skb, frag_iter) {
		int end;

//		WARN_ON(start > offset + len);

		end = start + frag_iter->len;
		if ((copy = end - offset) > 0) {
			if (copy > len)
				copy = len;
			if (skb_copy_bits(frag_iter, offset - start, to, copy))
				goto fault;
			if ((len -= copy) == 0)
				return 0;
			offset += copy;
			to = (u8 *)to + copy;//to     += copy;
		}
		start = end;
	}

	if (!len)
		return 0;

fault:
	return -EFAULT;
}
//EXPORT_SYMBOL(skb_copy_bits);

///*
// * Callback from splice_to_pipe(), if we need to release some pages
// * at the end of the spd in case we error'ed out in filling the pipe.
// */
//static void sock_spd_release(struct splice_pipe_desc *spd, unsigned int i)
//{
//	put_page(spd->pages[i]);
//}

//static inline struct page *linear_to_page(struct page *page, unsigned int *len,
//					  unsigned int *offset,
//					  struct sk_buff *skb, struct sock *sk)
//{
//	struct page *p = sk->sk_sndmsg_page;
//	unsigned int off;

//	if (!p) {
//new_page:
//		p = sk->sk_sndmsg_page = alloc_pages(sk->sk_allocation, 0);
//		if (!p)
//			return NULL;

//		off = sk->sk_sndmsg_off = 0;
//		/* hold one ref to this page until it's full */
//	} else {
//		unsigned int mlen;

//		off = sk->sk_sndmsg_off;
//		mlen = PAGE_SIZE - off;
//		if (mlen < 64 && mlen < *len) {
//			put_page(p);
//			goto new_page;
//		}

//		*len = min_t(unsigned int, *len, mlen);
//	}

//	memcpy(page_address(p) + off, page_address(page) + *offset, *len);
//	sk->sk_sndmsg_off += *len;
//	*offset = off;
//	get_page(p);

//	return p;
//}

///*
// * Fill page/offset/length into spd, if it can hold more pages.
// */
//static inline int spd_fill_page(struct splice_pipe_desc *spd,
//				struct pipe_inode_info *pipe, struct page *page,
//				unsigned int *len, unsigned int offset,
//				struct sk_buff *skb, int linear,
//				struct sock *sk)
//{
//	if (unlikely(spd->nr_pages == pipe->buffers))
//		return 1;

//	if (linear) {
//		page = linear_to_page(page, len, &offset, skb, sk);
//		if (!page)
//			return 1;
//	} else
//		get_page(page);

//	spd->pages[spd->nr_pages] = page;
//	spd->partial[spd->nr_pages].len = *len;
//	spd->partial[spd->nr_pages].offset = offset;
//	spd->nr_pages++;

//	return 0;
//}

//static inline void __segment_seek(struct page **page, unsigned int *poff,
//				  unsigned int *plen, unsigned int off)
//{
//	unsigned long n;

//	*poff += off;
//	n = *poff / PAGE_SIZE;
//	if (n)
//		*page = nth_page(*page, n);

//	*poff = *poff % PAGE_SIZE;
//	*plen -= off;
//}

//static inline int __splice_segment(struct page *page, unsigned int poff,
//				   unsigned int plen, unsigned int *off,
//				   unsigned int *len, struct sk_buff *skb,
//				   struct splice_pipe_desc *spd, int linear,
//				   struct sock *sk,
//				   struct pipe_inode_info *pipe)
//{
//	if (!*len)
//		return 1;

//	/* skip this segment if already processed */
//	if (*off >= plen) {
//		*off -= plen;
//		return 0;
//	}

//	/* ignore any bits we already processed */
//	if (*off) {
//		__segment_seek(&page, &poff, &plen, *off);
//		*off = 0;
//	}

//	do {
//		unsigned int flen = min(*len, plen);

//		/* the linear region may spread across several pages  */
//		flen = min_t(unsigned int, flen, PAGE_SIZE - poff);

//		if (spd_fill_page(spd, pipe, page, &flen, poff, skb, linear, sk))
//			return 1;

//		__segment_seek(&page, &poff, &plen, flen);
//		*len -= flen;

//	} while (*len && plen);

//	return 0;
//}

///*
// * Map linear and fragment data from the skb to spd. It reports failure if the
// * pipe is full or if we already spliced the requested length.
// */
//static int __skb_splice_bits(struct sk_buff *skb, struct pipe_inode_info *pipe,
//			     unsigned int *offset, unsigned int *len,
//			     struct splice_pipe_desc *spd, struct sock *sk)
//{
//	int seg;

//	/*
//	 * map the linear part
//	 */
//	if (__splice_segment(virt_to_page(skb->data),
//			     (unsigned long) skb->data & (PAGE_SIZE - 1),
//			     skb_headlen(skb),
//			     offset, len, skb, spd, 1, sk, pipe))
//		return 1;

//	/*
//	 * then map the fragments
//	 */
//	for (seg = 0; seg < skb_shinfo(skb)->nr_frags; seg++) {
//		const skb_frag_t *f = &skb_shinfo(skb)->frags[seg];

//		if (__splice_segment(skb_frag_page(f),
//				     f->page_offset, skb_frag_size(f),
//				     offset, len, skb, spd, 0, sk, pipe))
//			return 1;
//	}

//	return 0;
//}

///*
// * Map data from the skb to a pipe. Should handle both the linear part,
// * the fragments, and the frag list. It does NOT handle frag lists within
// * the frag list, if such a thing exists. We'd probably need to recurse to
// * handle that cleanly.
// */
//int skb_splice_bits(struct sk_buff *skb, unsigned int offset,
//		    struct pipe_inode_info *pipe, unsigned int tlen,
//		    unsigned int flags)
//{
//	struct partial_page partial[PIPE_DEF_BUFFERS];
//	struct page *pages[PIPE_DEF_BUFFERS];
//	struct splice_pipe_desc spd = {
//		.pages = pages,
//		.partial = partial,
//		.nr_pages_max = MAX_SKB_FRAGS,
//		.flags = flags,
//		.ops = &nosteal_pipe_buf_ops,
//		.spd_release = sock_spd_release,
//	};
//	struct sk_buff *frag_iter;
//	struct sock *sk = skb->sk;
//	int ret = 0;

//	if (splice_grow_spd(pipe, &spd))
//		return -ENOMEM;

//	/*
//	 * __skb_splice_bits() only fails if the output has no room left,
//	 * so no point in going over the frag_list for the error case.
//	 */
//	if (__skb_splice_bits(skb, pipe, &offset, &tlen, &spd, sk))
//		goto done;
//	else if (!tlen)
//		goto done;

//	/*
//	 * now see if we have a frag_list to map
//	 */
//	skb_walk_frags(skb, frag_iter) {
//		if (!tlen)
//			break;
//		if (__skb_splice_bits(frag_iter, pipe, &offset, &tlen, &spd, sk))
//			break;
//	}

//done:
//	if (spd.nr_pages) {
//		/*
//		 * Drop the socket lock, otherwise we have reverse
//		 * locking dependencies between sk_lock and i_mutex
//		 * here as compared to sendfile(). We enter here
//		 * with the socket lock held, and splice_to_pipe() will
//		 * grab the pipe inode lock. For sendfile() emulation,
//		 * we call into ->sendpage() with the i_mutex lock held
//		 * and networking will grab the socket lock.
//		 */
//		release_sock(sk);
//		ret = splice_to_pipe(pipe, &spd);
//		lock_sock(sk);
//	}

//	splice_shrink_spd(&spd);
//	return ret;
//}

///**
// *	skb_store_bits - store bits from kernel buffer to skb
// *	@skb: destination buffer
// *	@offset: offset in destination
// *	@from: source buffer
// *	@len: number of bytes to copy
// *
// *	Copy the specified number of bytes from the source buffer to the
// *	destination skb.  This function handles all the messy bits of
// *	traversing fragment lists and such.
// */

//int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len)
//{
//	int start = skb_headlen(skb);
//	struct sk_buff *frag_iter;
//	int i, copy;

//	if (offset > (int)skb->len - len)
//		goto fault;

//	if ((copy = start - offset) > 0) {
//		if (copy > len)
//			copy = len;
//		skb_copy_to_linear_data_offset(skb, offset, from, copy);
//		if ((len -= copy) == 0)
//			return 0;
//		offset += copy;
//		from += copy;
//	}

//	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
//		skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
//		int end;

//		WARN_ON(start > offset + len);

//		end = start + skb_frag_size(frag);
//		if ((copy = end - offset) > 0) {
//			u8 *vaddr;

//			if (copy > len)
//				copy = len;

//			vaddr = kmap_skb_frag(frag);
//			memcpy(vaddr + frag->page_offset + offset - start,
//			       from, copy);
//			kunmap_skb_frag(vaddr);

//			if ((len -= copy) == 0)
//				return 0;
//			offset += copy;
//			from += copy;
//		}
//		start = end;
//	}

//	skb_walk_frags(skb, frag_iter) {
//		int end;

//		WARN_ON(start > offset + len);

//		end = start + frag_iter->len;
//		if ((copy = end - offset) > 0) {
//			if (copy > len)
//				copy = len;
//			if (skb_store_bits(frag_iter, offset - start,
//					   from, copy))
//				goto fault;
//			if ((len -= copy) == 0)
//				return 0;
//			offset += copy;
//			from += copy;
//		}
//		start = end;
//	}
//	if (!len)
//		return 0;

//fault:
//	return -EFAULT;
//}
//EXPORT_SYMBOL(skb_store_bits);

///* Checksum skb data. */

//__wsum skb_checksum(const struct sk_buff *skb, int offset,
//			  int len, __wsum csum)
//{
//	int start = skb_headlen(skb);
//	int i, copy = start - offset;
//	struct sk_buff *frag_iter;
//	int pos = 0;

//	/* Checksum header. */
//	if (copy > 0) {
//		if (copy > len)
//			copy = len;
//		csum = csum_partial(skb->data + offset, copy, csum);
//		if ((len -= copy) == 0)
//			return csum;
//		offset += copy;
//		pos	= copy;
//	}

//	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
//		int end;

//		WARN_ON(start > offset + len);

//		end = start + skb_frag_size(&skb_shinfo(skb)->frags[i]);
//		if ((copy = end - offset) > 0) {
//			__wsum csum2;
//			u8 *vaddr;
//			skb_frag_t *frag = &skb_shinfo(skb)->frags[i];

//			if (copy > len)
//				copy = len;
//			vaddr = kmap_skb_frag(frag);
//			csum2 = csum_partial(vaddr + frag->page_offset +
//					     offset - start, copy, 0);
//			kunmap_skb_frag(vaddr);
//			csum = csum_block_add(csum, csum2, pos);
//			if (!(len -= copy))
//				return csum;
//			offset += copy;
//			pos    += copy;
//		}
//		start = end;
//	}

//	skb_walk_frags(skb, frag_iter) {
//		int end;

//		WARN_ON(start > offset + len);

//		end = start + frag_iter->len;
//		if ((copy = end - offset) > 0) {
//			__wsum csum2;
//			if (copy > len)
//				copy = len;
//			csum2 = skb_checksum(frag_iter, offset - start,
//					     copy, 0);
//			csum = csum_block_add(csum, csum2, pos);
//			if ((len -= copy) == 0)
//				return csum;
//			offset += copy;
//			pos    += copy;
//		}
//		start = end;
//	}
//	BUG_ON(len);

//	return csum;
//}
//EXPORT_SYMBOL(skb_checksum);

///* Both of above in one bottle. */

//__wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset,
//				    u8 *to, int len, __wsum csum)
//{
//	int start = skb_headlen(skb);
//	int i, copy = start - offset;
//	struct sk_buff *frag_iter;
//	int pos = 0;

//	/* Copy header. */
//	if (copy > 0) {
//		if (copy > len)
//			copy = len;
//		csum = csum_partial_copy_nocheck(skb->data + offset, to,
//						 copy, csum);
//		if ((len -= copy) == 0)
//			return csum;
//		offset += copy;
//		to     += copy;
//		pos	= copy;
//	}

//	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
//		int end;

//		WARN_ON(start > offset + len);

//		end = start + skb_frag_size(&skb_shinfo(skb)->frags[i]);
//		if ((copy = end - offset) > 0) {
//			__wsum csum2;
//			u8 *vaddr;
//			skb_frag_t *frag = &skb_shinfo(skb)->frags[i];

//			if (copy > len)
//				copy = len;
//			vaddr = kmap_skb_frag(frag);
//			csum2 = csum_partial_copy_nocheck(vaddr +
//							  frag->page_offset +
//							  offset - start, to,
//							  copy, 0);
//			kunmap_skb_frag(vaddr);
//			csum = csum_block_add(csum, csum2, pos);
//			if (!(len -= copy))
//				return csum;
//			offset += copy;
//			to     += copy;
//			pos    += copy;
//		}
//		start = end;
//	}

//	skb_walk_frags(skb, frag_iter) {
//		__wsum csum2;
//		int end;

//		WARN_ON(start > offset + len);

//		end = start + frag_iter->len;
//		if ((copy = end - offset) > 0) {
//			if (copy > len)
//				copy = len;
//			csum2 = skb_copy_and_csum_bits(frag_iter,
//						       offset - start,
//						       to, copy, 0);
//			csum = csum_block_add(csum, csum2, pos);
//			if ((len -= copy) == 0)
//				return csum;
//			offset += copy;
//			to     += copy;
//			pos    += copy;
//		}
//		start = end;
//	}
//	BUG_ON(len);
//	return csum;
//}
//EXPORT_SYMBOL(skb_copy_and_csum_bits);

//void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to)
//{
//	__wsum csum;
//	long csstart;

//	if (skb->ip_summed == CHECKSUM_PARTIAL)
//		csstart = skb_checksum_start_offset(skb);
//	else
//		csstart = skb_headlen(skb);

//	BUG_ON(csstart > skb_headlen(skb));

//	skb_copy_from_linear_data(skb, to, csstart);

//	csum = 0;
//	if (csstart != skb->len)
//		csum = skb_copy_and_csum_bits(skb, csstart, to + csstart,
//					      skb->len - csstart, 0);

//	if (skb->ip_summed == CHECKSUM_PARTIAL) {
//		long csstuff = csstart + skb->csum_offset;

//		*((__sum16 *)(to + csstuff)) = csum_fold(csum);
//	}
//}
//EXPORT_SYMBOL(skb_copy_and_csum_dev);

/**
 *	skb_dequeue - remove from the head of the queue
 *	@list: list to dequeue from
 *
 *	Remove the head of the list. The list lock is taken so the function
 *	may be used safely with other locking list functions. The head item is
 *	returned or %NULL if the list is empty.
 */

struct sk_buff *skb_dequeue(struct sk_buff_head *list)
{
	unsigned long flags;
	struct sk_buff *result;

	spin_lock_irqsave(&list->lock, flags);
	result = __skb_dequeue(list);
	spin_unlock_irqrestore(&list->lock, flags);
	return result;
}
//EXPORT_SYMBOL(skb_dequeue);

///**
// *	skb_dequeue_tail - remove from the tail of the queue
// *	@list: list to dequeue from
// *
// *	Remove the tail of the list. The list lock is taken so the function
// *	may be used safely with other locking list functions. The tail item is
// *	returned or %NULL if the list is empty.
// */
//struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list)
//{
//	unsigned long flags;
//	struct sk_buff *result;

//	spin_lock_irqsave(&list->lock, flags);
//	result = __skb_dequeue_tail(list);
//	spin_unlock_irqrestore(&list->lock, flags);
//	return result;
//}
//EXPORT_SYMBOL(skb_dequeue_tail);

///**
// *	skb_queue_purge - empty a list
// *	@list: list to empty
// *
// *	Delete all buffers on an &sk_buff list. Each buffer is removed from
// *	the list and one reference dropped. This function takes the list
// *	lock and is atomic with respect to other list locking functions.
// */
//void skb_queue_purge(struct sk_buff_head *list)
//{
//	struct sk_buff *skb;
//	while ((skb = skb_dequeue(list)) != NULL)
//		kfree_skb(skb);
//}
//EXPORT_SYMBOL(skb_queue_purge);

///**
// *	skb_queue_head - queue a buffer at the list head
// *	@list: list to use
// *	@newsk: buffer to queue
// *
// *	Queue a buffer at the start of the list. This function takes the
// *	list lock and can be used safely with other locking &sk_buff functions
// *	safely.
// *
// *	A buffer cannot be placed on two lists at the same time.
// */
//void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk)
//{
//	unsigned long flags;

//	spin_lock_irqsave(&list->lock, flags);
//	__skb_queue_head(list, newsk);
//	spin_unlock_irqrestore(&list->lock, flags);
//}
//EXPORT_SYMBOL(skb_queue_head);

/**
 *	skb_queue_tail - queue a buffer at the list tail
 *	@list: list to use
 *	@newsk: buffer to queue
 *
 *	Queue a buffer at the tail of the list. This function takes the
 *	list lock and can be used safely with other locking &sk_buff functions
 *	safely.
 *
 *	A buffer cannot be placed on two lists at the same time.
 */
void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk)
{
	unsigned long flags;

	spin_lock_irqsave(&list->lock, flags);
	__skb_queue_tail(list, newsk);
	spin_unlock_irqrestore(&list->lock, flags);
}
//EXPORT_SYMBOL(skb_queue_tail);

///**
// *	skb_unlink	-	remove a buffer from a list
// *	@skb: buffer to remove
// *	@list: list to use
// *
// *	Remove a packet from a list. The list locks are taken and this
// *	function is atomic with respect to other list locked calls
// *
// *	You must know what list the SKB is on.
// */
//void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
//{
//	unsigned long flags;

//	spin_lock_irqsave(&list->lock, flags);
//	__skb_unlink(skb, list);
//	spin_unlock_irqrestore(&list->lock, flags);
//}
//EXPORT_SYMBOL(skb_unlink);

///**
// *	skb_append	-	append a buffer
// *	@old: buffer to insert after
// *	@newsk: buffer to insert
// *	@list: list to use
// *
// *	Place a packet after a given packet in a list. The list locks are taken
// *	and this function is atomic with respect to other list locked calls.
// *	A buffer cannot be placed on two lists at the same time.
// */
//void skb_append(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list)
//{
//	unsigned long flags;

//	spin_lock_irqsave(&list->lock, flags);
//	__skb_queue_after(list, old, newsk);
//	spin_unlock_irqrestore(&list->lock, flags);
//}
//EXPORT_SYMBOL(skb_append);

///**
// *	skb_insert	-	insert a buffer
// *	@old: buffer to insert before
// *	@newsk: buffer to insert
// *	@list: list to use
// *
// *	Place a packet before a given packet in a list. The list locks are
// * 	taken and this function is atomic with respect to other list locked
// *	calls.
// *
// *	A buffer cannot be placed on two lists at the same time.
// */
//void skb_insert(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list)
//{
//	unsigned long flags;

//	spin_lock_irqsave(&list->lock, flags);
//	__skb_insert(newsk, old->prev, old, list);
//	spin_unlock_irqrestore(&list->lock, flags);
//}
//EXPORT_SYMBOL(skb_insert);

//static inline void skb_split_inside_header(struct sk_buff *skb,
//					   struct sk_buff* skb1,
//					   const u32 len, const int pos)
//{
//	int i;

//	skb_copy_from_linear_data_offset(skb, len, skb_put(skb1, pos - len),
//					 pos - len);
//	/* And move data appendix as is. */
//	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
//		skb_shinfo(skb1)->frags[i] = skb_shinfo(skb)->frags[i];

//	skb_shinfo(skb1)->nr_frags = skb_shinfo(skb)->nr_frags;
//	skb_shinfo(skb)->nr_frags  = 0;
//	skb1->data_len		   = skb->data_len;
//	skb1->len		   += skb1->data_len;
//	skb->data_len		   = 0;
//	skb->len		   = len;
//	skb_set_tail_pointer(skb, len);
//}

//static inline void skb_split_no_header(struct sk_buff *skb,
//				       struct sk_buff* skb1,
//				       const u32 len, int pos)
//{
//	int i, k = 0;
//	const int nfrags = skb_shinfo(skb)->nr_frags;

//	skb_shinfo(skb)->nr_frags = 0;
//	skb1->len		  = skb1->data_len = skb->len - len;
//	skb->len		  = len;
//	skb->data_len		  = len - pos;

//	for (i = 0; i < nfrags; i++) {
//		int size = skb_frag_size(&skb_shinfo(skb)->frags[i]);

//		if (pos + size > len) {
//			skb_shinfo(skb1)->frags[k] = skb_shinfo(skb)->frags[i];

//			if (pos < len) {
//				/* Split frag.
//				 * We have two variants in this case:
//				 * 1. Move all the frag to the second
//				 *    part, if it is possible. F.e.
//				 *    this approach is mandatory for TUX,
//				 *    where splitting is expensive.
//				 * 2. Split is accurately. We make this.
//				 */
//				skb_frag_ref(skb, i);
//				skb_shinfo(skb1)->frags[0].page_offset += len - pos;
//				skb_frag_size_sub(&skb_shinfo(skb1)->frags[0], len - pos);
//				skb_frag_size_set(&skb_shinfo(skb)->frags[i], len - pos);
//				skb_shinfo(skb)->nr_frags++;
//			}
//			k++;
//		} else
//			skb_shinfo(skb)->nr_frags++;
//		pos += size;
//	}
//	skb_shinfo(skb1)->nr_frags = k;
//}

///**
// * skb_split - Split fragmented skb to two parts at length len.
// * @skb: the buffer to split
// * @skb1: the buffer to receive the second part
// * @len: new length for skb
// */
//void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len)
//{
//	int pos = skb_headlen(skb);

//	if (len < pos)	/* Split line is inside header. */
//		skb_split_inside_header(skb, skb1, len, pos);
//	else		/* Second chunk has no header, nothing to copy. */
//		skb_split_no_header(skb, skb1, len, pos);
//}
//EXPORT_SYMBOL(skb_split);

///* Shifting from/to a cloned skb is a no-go.
// *
// * Caller cannot keep skb_shinfo related pointers past calling here!
// */
//static int skb_prepare_for_shift(struct sk_buff *skb)
//{
//	return skb_cloned(skb) && pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
//}

///**
// * skb_shift - Shifts paged data partially from skb to another
// * @tgt: buffer into which tail data gets added
// * @skb: buffer from which the paged data comes from
// * @shiftlen: shift up to this many bytes
// *
// * Attempts to shift up to shiftlen worth of bytes, which may be less than
// * the length of the skb, from skb to tgt. Returns number bytes shifted.
// * It's up to caller to free skb if everything was shifted.
// *
// * If @tgt runs out of frags, the whole operation is aborted.
// *
// * Skb cannot include anything else but paged data while tgt is allowed
// * to have non-paged data as well.
// *
// * TODO: full sized shift could be optimized but that would need
// * specialized skb free'er to handle frags without up-to-date nr_frags.
// */
//int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen)
//{
//	int from, to, merge, todo;
//	struct skb_frag_struct *fragfrom, *fragto;

//	BUG_ON(shiftlen > skb->len);
//	BUG_ON(skb_headlen(skb));	/* Would corrupt stream */

//	todo = shiftlen;
//	from = 0;
//	to = skb_shinfo(tgt)->nr_frags;
//	fragfrom = &skb_shinfo(skb)->frags[from];

//	/* Actual merge is delayed until the point when we know we can
//	 * commit all, so that we don't have to undo partial changes
//	 */
//	if (!to ||
//	    !skb_can_coalesce(tgt, to, skb_frag_page(fragfrom),
//			      fragfrom->page_offset)) {
//		merge = -1;
//	} else {
//		merge = to - 1;

//		todo -= skb_frag_size(fragfrom);
//		if (todo < 0) {
//			if (skb_prepare_for_shift(skb) ||
//			    skb_prepare_for_shift(tgt))
//				return 0;

//			/* All previous frag pointers might be stale! */
//			fragfrom = &skb_shinfo(skb)->frags[from];
//			fragto = &skb_shinfo(tgt)->frags[merge];

//			skb_frag_size_add(fragto, shiftlen);
//			skb_frag_size_sub(fragfrom, shiftlen);
//			fragfrom->page_offset += shiftlen;

//			goto onlymerged;
//		}

//		from++;
//	}

//	/* Skip full, not-fitting skb to avoid expensive operations */
//	if ((shiftlen == skb->len) &&
//	    (skb_shinfo(skb)->nr_frags - from) > (MAX_SKB_FRAGS - to))
//		return 0;

//	if (skb_prepare_for_shift(skb) || skb_prepare_for_shift(tgt))
//		return 0;

//	while ((todo > 0) && (from < skb_shinfo(skb)->nr_frags)) {
//		if (to == MAX_SKB_FRAGS)
//			return 0;

//		fragfrom = &skb_shinfo(skb)->frags[from];
//		fragto = &skb_shinfo(tgt)->frags[to];

//		if (todo >= skb_frag_size(fragfrom)) {
//			*fragto = *fragfrom;
//			todo -= skb_frag_size(fragfrom);
//			from++;
//			to++;

//		} else {
//			__skb_frag_ref(fragfrom);
//			fragto->page = fragfrom->page;
//			fragto->page_offset = fragfrom->page_offset;
//			skb_frag_size_set(fragto, todo);

//			fragfrom->page_offset += todo;
//			skb_frag_size_sub(fragfrom, todo);
//			todo = 0;

//			to++;
//			break;
//		}
//	}

//	/* Ready to "commit" this state change to tgt */
//	skb_shinfo(tgt)->nr_frags = to;

//	if (merge >= 0) {
//		fragfrom = &skb_shinfo(skb)->frags[0];
//		fragto = &skb_shinfo(tgt)->frags[merge];

//		skb_frag_size_add(fragto, skb_frag_size(fragfrom));
//		__skb_frag_unref(fragfrom);
//	}

//	/* Reposition in the original skb */
//	to = 0;
//	while (from < skb_shinfo(skb)->nr_frags)
//		skb_shinfo(skb)->frags[to++] = skb_shinfo(skb)->frags[from++];
//	skb_shinfo(skb)->nr_frags = to;

//	BUG_ON(todo > 0 && !skb_shinfo(skb)->nr_frags);

//onlymerged:
//	/* Most likely the tgt won't ever need its checksum anymore, skb on
//	 * the other hand might need it if it needs to be resent
//	 */
//	tgt->ip_summed = CHECKSUM_PARTIAL;
//	skb->ip_summed = CHECKSUM_PARTIAL;

//	/* Yak, is it really working this way? Some helper please? */
//	skb->len -= shiftlen;
//	skb->data_len -= shiftlen;
//	skb->truesize -= shiftlen;
//	tgt->len += shiftlen;
//	tgt->data_len += shiftlen;
//	tgt->truesize += shiftlen;

//	return shiftlen;
//}

///**
// * skb_prepare_seq_read - Prepare a sequential read of skb data
// * @skb: the buffer to read
// * @from: lower offset of data to be read
// * @to: upper offset of data to be read
// * @st: state variable
// *
// * Initializes the specified state variable. Must be called before
// * invoking skb_seq_read() for the first time.
// */
//void skb_prepare_seq_read(struct sk_buff *skb, unsigned int from,
//			  unsigned int to, struct skb_seq_state *st)
//{
//	st->lower_offset = from;
//	st->upper_offset = to;
//	st->root_skb = st->cur_skb = skb;
//	st->frag_idx = st->stepped_offset = 0;
//	st->frag_data = NULL;
//}
//EXPORT_SYMBOL(skb_prepare_seq_read);

///**
// * skb_seq_read - Sequentially read skb data
// * @consumed: number of bytes consumed by the caller so far
// * @data: destination pointer for data to be returned
// * @st: state variable
// *
// * Reads a block of skb data at &consumed relative to the
// * lower offset specified to skb_prepare_seq_read(). Assigns
// * the head of the data block to &data and returns the length
// * of the block or 0 if the end of the skb data or the upper
// * offset has been reached.
// *
// * The caller is not required to consume all of the data
// * returned, i.e. &consumed is typically set to the number
// * of bytes already consumed and the next call to
// * skb_seq_read() will return the remaining part of the block.
// *
// * Note 1: The size of each block of data returned can be arbitrary,
// *       this limitation is the cost for zerocopy seqeuental
// *       reads of potentially non linear data.
// *
// * Note 2: Fragment lists within fragments are not implemented
// *       at the moment, state->root_skb could be replaced with
// *       a stack for this purpose.
// */
//unsigned int skb_seq_read(unsigned int consumed, const u8 **data,
//			  struct skb_seq_state *st)
//{
//	unsigned int block_limit, abs_offset = consumed + st->lower_offset;
//	skb_frag_t *frag;

//	if (unlikely(abs_offset >= st->upper_offset))
//		return 0;

//next_skb:
//	block_limit = skb_headlen(st->cur_skb) + st->stepped_offset;

//	if (abs_offset < block_limit && !st->frag_data) {
//		*data = st->cur_skb->data + (abs_offset - st->stepped_offset);
//		return block_limit - abs_offset;
//	}

//	if (st->frag_idx == 0 && !st->frag_data)
//		st->stepped_offset += skb_headlen(st->cur_skb);

//	while (st->frag_idx < skb_shinfo(st->cur_skb)->nr_frags) {
//		frag = &skb_shinfo(st->cur_skb)->frags[st->frag_idx];
//		block_limit = skb_frag_size(frag) + st->stepped_offset;

//		if (abs_offset < block_limit) {
//			if (!st->frag_data)
//				st->frag_data = kmap_skb_frag(frag);

//			*data = (u8 *) st->frag_data + frag->page_offset +
//				(abs_offset - st->stepped_offset);

//			return block_limit - abs_offset;
//		}

//		if (st->frag_data) {
//			kunmap_skb_frag(st->frag_data);
//			st->frag_data = NULL;
//		}

//		st->frag_idx++;
//		st->stepped_offset += skb_frag_size(frag);
//	}

//	if (st->frag_data) {
//		kunmap_skb_frag(st->frag_data);
//		st->frag_data = NULL;
//	}

//	if (st->root_skb == st->cur_skb && skb_has_frag_list(st->root_skb)) {
//		st->cur_skb = skb_shinfo(st->root_skb)->frag_list;
//		st->frag_idx = 0;
//		goto next_skb;
//	} else if (st->cur_skb->next) {
//		st->cur_skb = st->cur_skb->next;
//		st->frag_idx = 0;
//		goto next_skb;
//	}

//	return 0;
//}
//EXPORT_SYMBOL(skb_seq_read);

///**
// * skb_abort_seq_read - Abort a sequential read of skb data
// * @st: state variable
// *
// * Must be called if skb_seq_read() was not called until it
// * returned 0.
// */
//void skb_abort_seq_read(struct skb_seq_state *st)
//{
//	if (st->frag_data)
//		kunmap_skb_frag(st->frag_data);
//}
//EXPORT_SYMBOL(skb_abort_seq_read);

//#define TS_SKB_CB(state)	((struct skb_seq_state *) &((state)->cb))

//static unsigned int skb_ts_get_next_block(unsigned int offset, const u8 **text,
//					  struct ts_config *conf,
//					  struct ts_state *state)
//{
//	return skb_seq_read(offset, text, TS_SKB_CB(state));
//}

//static void skb_ts_finish(struct ts_config *conf, struct ts_state *state)
//{
//	skb_abort_seq_read(TS_SKB_CB(state));
//}

///**
// * skb_find_text - Find a text pattern in skb data
// * @skb: the buffer to look in
// * @from: search offset
// * @to: search limit
// * @config: textsearch configuration
// * @state: uninitialized textsearch state variable
// *
// * Finds a pattern in the skb data according to the specified
// * textsearch configuration. Use textsearch_next() to retrieve
// * subsequent occurrences of the pattern. Returns the offset
// * to the first occurrence or UINT_MAX if no match was found.
// */
//unsigned int skb_find_text(struct sk_buff *skb, unsigned int from,
//			   unsigned int to, struct ts_config *config,
//			   struct ts_state *state)
//{
//	unsigned int ret;

//	config->get_next_block = skb_ts_get_next_block;
//	config->finish = skb_ts_finish;

//	skb_prepare_seq_read(skb, from, to, TS_SKB_CB(state));

//	ret = textsearch_find(config, state);
//	return (ret <= to - from ? ret : UINT_MAX);
//}
//EXPORT_SYMBOL(skb_find_text);

///**
// * skb_append_datato_frags: - append the user data to a skb
// * @sk: sock  structure
// * @skb: skb structure to be appened with user data.
// * @getfrag: call back function to be used for getting the user data
// * @from: pointer to user message iov
// * @length: length of the iov message
// *
// * Description: This procedure append the user data in the fragment part
// * of the skb if any page alloc fails user this procedure returns  -ENOMEM
// */
//int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,
//			int (*getfrag)(void *from, char *to, int offset,
//					int len, int odd, struct sk_buff *skb),
//			void *from, int length)
//{
//	int frg_cnt = 0;
//	skb_frag_t *frag = NULL;
//	struct page *page = NULL;
//	int copy, left;
//	int offset = 0;
//	int ret;

//	do {
//		/* Return error if we don't have space for new frag */
//		frg_cnt = skb_shinfo(skb)->nr_frags;
//		if (frg_cnt >= MAX_SKB_FRAGS)
//			return -EFAULT;

//		/* allocate a new page for next frag */
//		page = alloc_pages(sk->sk_allocation, 0);

//		/* If alloc_page fails just return failure and caller will
//		 * free previous allocated pages by doing kfree_skb()
//		 */
//		if (page == NULL)
//			return -ENOMEM;

//		/* initialize the next frag */
//		skb_fill_page_desc(skb, frg_cnt, page, 0, 0);
//		skb->truesize += PAGE_SIZE;
//		atomic_add(PAGE_SIZE, &sk->sk_wmem_alloc);

//		/* get the new initialized frag */
//		frg_cnt = skb_shinfo(skb)->nr_frags;
//		frag = &skb_shinfo(skb)->frags[frg_cnt - 1];

//		/* copy the user data to page */
//		left = PAGE_SIZE - frag->page_offset;
//		copy = (length > left)? left : length;

//		ret = getfrag(from, skb_frag_address(frag) + skb_frag_size(frag),
//			    offset, copy, 0, skb);
//		if (ret < 0)
//			return -EFAULT;

//		/* copy was successful so update the size parameters */
//		skb_frag_size_add(frag, copy);
//		skb->len += copy;
//		skb->data_len += copy;
//		offset += copy;
//		length -= copy;

//	} while (length > 0);

//	return 0;
//}
//EXPORT_SYMBOL(skb_append_datato_frags);

///**
// *	skb_pull_rcsum - pull skb and update receive checksum
// *	@skb: buffer to update
// *	@len: length of data pulled
// *
// *	This function performs an skb_pull on the packet and updates
// *	the CHECKSUM_COMPLETE checksum.  It should be used on
// *	receive path processing instead of skb_pull unless you know
// *	that the checksum difference is zero (e.g., a valid IP header)
// *	or you are setting ip_summed to CHECKSUM_NONE.
// */
//unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len)
//{
//	unsigned char *data = skb->data;

//	BUG_ON(len > skb->len);
//	__skb_pull(skb, len);
//	skb_postpull_rcsum(skb, data, len);
//	return skb->data;
//}
////EXPORT_SYMBOL_GPL(skb_pull_rcsum);

///**
// *	skb_segment - Perform protocol segmentation on skb.
// *	@skb: buffer to segment
// *	@features: features for the output path (see dev->features)
// *
// *	This function performs segmentation on the given skb.  It returns
// *	a pointer to the first in a list of new skbs for the segments.
// *	In case of error it returns (void *)(err).
// */
//struct sk_buff *skb_segment(struct sk_buff *skb, u32 features)
//{
//	struct sk_buff *segs = NULL;
//	struct sk_buff *tail = NULL;
//	struct sk_buff *fskb = skb_shinfo(skb)->frag_list;
//	unsigned int mss = skb_shinfo(skb)->gso_size;
//	unsigned int doffset = skb->data - skb_mac_header(skb);
//	unsigned int offset = doffset;
//	unsigned int headroom;
//	unsigned int len;
//	int sg = !!(features & NETIF_F_SG);
//	int nfrags = skb_shinfo(skb)->nr_frags;
//	int err = -ENOMEM;
//	int i = 0;
//	int pos;

//	__skb_push(skb, doffset);
//	headroom = skb_headroom(skb);
//	pos = skb_headlen(skb);

//	do {
//		struct sk_buff *nskb;
//		skb_frag_t *frag;
//		int hsize;
//		int size;

//		len = skb->len - offset;
//		if (len > mss)
//			len = mss;

//		hsize = skb_headlen(skb) - offset;
//		if (hsize < 0)
//			hsize = 0;
//		if (hsize > len || !sg)
//			hsize = len;

//		if (!hsize && i >= nfrags) {
//			BUG_ON(fskb->len != len);

//			pos += len;
//			nskb = skb_clone(fskb, GFP_ATOMIC);
//			fskb = fskb->next;

//			if (unlikely(!nskb))
//				goto err;

//			hsize = skb_end_offset(nskb);
//			if (skb_cow_head(nskb, doffset + headroom)) {
//				kfree_skb(nskb);
//				goto err;
//			}

//			nskb->truesize += skb_end_offset(nskb) - hsize;
//			skb_release_head_state(nskb);
//			__skb_push(nskb, doffset);
//		} else {
//			nskb = alloc_skb(hsize + doffset + headroom,
//					 GFP_ATOMIC);

//			if (unlikely(!nskb))
//				goto err;

//			skb_reserve(nskb, headroom);
//			__skb_put(nskb, doffset);
//		}

//		if (segs)
//			tail->next = nskb;
//		else
//			segs = nskb;
//		tail = nskb;

//		__copy_skb_header(nskb, skb);
//		nskb->mac_len = skb->mac_len;

//		/* nskb and skb might have different headroom */
//		if (nskb->ip_summed == CHECKSUM_PARTIAL)
//			nskb->csum_start += skb_headroom(nskb) - headroom;

//		skb_reset_mac_header(nskb);
//		skb_set_network_header(nskb, skb->mac_len);
//		nskb->transport_header = (nskb->network_header +
//					  skb_network_header_len(skb));
//		skb_copy_from_linear_data(skb, nskb->data, doffset);

//		if (fskb != skb_shinfo(skb)->frag_list)
//			continue;

//		if (!sg) {
//			nskb->ip_summed = CHECKSUM_NONE;
//			nskb->csum = skb_copy_and_csum_bits(skb, offset,
//							    skb_put(nskb, len),
//							    len, 0);
//			continue;
//		}

//		frag = skb_shinfo(nskb)->frags;

//		skb_copy_from_linear_data_offset(skb, offset,
//						 skb_put(nskb, hsize), hsize);

//		while (pos < offset + len && i < nfrags) {
//			if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
//				goto err;

//			*frag = skb_shinfo(skb)->frags[i];
//			__skb_frag_ref(frag);
//			size = skb_frag_size(frag);

//			if (pos < offset) {
//				frag->page_offset += offset - pos;
//				skb_frag_size_sub(frag, offset - pos);
//			}

//			skb_shinfo(nskb)->nr_frags++;

//			if (pos + size <= offset + len) {
//				i++;
//				pos += size;
//			} else {
//				skb_frag_size_sub(frag, pos + size - (offset + len));
//				goto skip_fraglist;
//			}

//			frag++;
//		}

//		if (pos < offset + len) {
//			struct sk_buff *fskb2 = fskb;

//			BUG_ON(pos + fskb->len != offset + len);

//			pos += fskb->len;
//			fskb = fskb->next;

//			if (fskb2->next) {
//				fskb2 = skb_clone(fskb2, GFP_ATOMIC);
//				if (!fskb2)
//					goto err;
//			} else
//				skb_get(fskb2);

//			SKB_FRAG_ASSERT(nskb);
//			skb_shinfo(nskb)->frag_list = fskb2;
//		}

//skip_fraglist:
//		nskb->data_len = len - hsize;
//		nskb->len += nskb->data_len;
//		nskb->truesize += nskb->data_len;
//	} while ((offset += len) < skb->len);

//	return segs;

//err:
//	while ((skb = segs)) {
//		segs = skb->next;
//		kfree_skb(skb);
//	}
//	return (void *)(err);
//}
////EXPORT_SYMBOL_GPL(skb_segment);

//int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb)
//{
//	struct sk_buff *p = *head;
//	struct sk_buff *nskb;
//	struct skb_shared_info *skbinfo = skb_shinfo(skb);
//	struct skb_shared_info *pinfo = skb_shinfo(p);
//	unsigned int headroom;
//	unsigned int len = skb_gro_len(skb);
//	unsigned int offset = skb_gro_offset(skb);
//	unsigned int headlen = skb_headlen(skb);

//	if (p->len + len >= 65536)
//		return -E2BIG;

//	if (pinfo->frag_list)
//		goto merge;
//	else if (headlen <= offset) {
//		skb_frag_t *frag;
//		skb_frag_t *frag2;
//		int i = skbinfo->nr_frags;
//		int nr_frags = pinfo->nr_frags + i;

//		offset -= headlen;

//		if (nr_frags > MAX_SKB_FRAGS)
//			return -E2BIG;

//		pinfo->nr_frags = nr_frags;
//		skbinfo->nr_frags = 0;

//		frag = pinfo->frags + nr_frags;
//		frag2 = skbinfo->frags + i;
//		do {
//			*--frag = *--frag2;
//		} while (--i);

//		frag->page_offset += offset;
//		skb_frag_size_sub(frag, offset);

//		skb->truesize -= skb->data_len;
//		skb->len -= skb->data_len;
//		skb->data_len = 0;

//		NAPI_GRO_CB(skb)->free = 1;
//		goto done;
//	} else if (skb_gro_len(p) != pinfo->gso_size)
//		return -E2BIG;

//	headroom = skb_headroom(p);
//	nskb = alloc_skb(headroom + skb_gro_offset(p), GFP_ATOMIC);
//	if (unlikely(!nskb))
//		return -ENOMEM;

//	__copy_skb_header(nskb, p);
//	nskb->mac_len = p->mac_len;

//	skb_reserve(nskb, headroom);
//	__skb_put(nskb, skb_gro_offset(p));

//	skb_set_mac_header(nskb, skb_mac_header(p) - p->data);
//	skb_set_network_header(nskb, skb_network_offset(p));
//	skb_set_transport_header(nskb, skb_transport_offset(p));

//	__skb_pull(p, skb_gro_offset(p));
//	memcpy(skb_mac_header(nskb), skb_mac_header(p),
//	       p->data - skb_mac_header(p));

//	*NAPI_GRO_CB(nskb) = *NAPI_GRO_CB(p);
//	skb_shinfo(nskb)->frag_list = p;
//	skb_shinfo(nskb)->gso_size = pinfo->gso_size;
//	pinfo->gso_size = 0;
//	skb_header_release(p);
//	nskb->prev = p;

//	nskb->data_len += p->len;
//	nskb->truesize += p->len;
//	nskb->len += p->len;

//	*head = nskb;
//	nskb->next = p->next;
//	p->next = NULL;

//	p = nskb;

//merge:
//	if (offset > headlen) {
//		unsigned int eat = offset - headlen;

//		skbinfo->frags[0].page_offset += eat;
//		skb_frag_size_sub(&skbinfo->frags[0], eat);
//		skb->data_len -= eat;
//		skb->len -= eat;
//		offset = headlen;
//	}

//	__skb_pull(skb, offset);

//	p->prev->next = skb;
//	p->prev = skb;
//	skb_header_release(skb);

//done:
//	NAPI_GRO_CB(p)->count++;
//	p->data_len += len;
//	p->truesize += len;
//	p->len += len;

//	NAPI_GRO_CB(skb)->same_flow = 1;
//	return 0;
//}
////EXPORT_SYMBOL_GPL(skb_gro_receive);

//void __init skb_init(void)
//{
//	skbuff_head_cache = kmem_cache_create("skbuff_head_cache",
//					      sizeof(struct sk_buff),
//					      0,
//					      SLAB_HWCACHE_ALIGN|SLAB_PANIC,
//					      NULL);
//	skbuff_fclone_cache = kmem_cache_create("skbuff_fclone_cache",
//						(2*sizeof(struct sk_buff)) +
//						sizeof(atomic_t),
//						0,
//						SLAB_HWCACHE_ALIGN|SLAB_PANIC,
//						NULL);
//}

///**
// *	skb_to_sgvec - Fill a scatter-gather list from a socket buffer
// *	@skb: Socket buffer containing the buffers to be mapped
// *	@sg: The scatter-gather list to map into
// *	@offset: The offset into the buffer's contents to start mapping
// *	@len: Length of buffer space to be mapped
// *
// *	Fill the specified scatter-gather list with mappings/pointers into a
// *	region of the buffer space attached to a socket buffer.
// */
//static int
//__skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
//{
//	int start = skb_headlen(skb);
//	int i, copy = start - offset;
//	struct sk_buff *frag_iter;
//	int elt = 0;

//	if (copy > 0) {
//		if (copy > len)
//			copy = len;
//		sg_set_buf(sg, skb->data + offset, copy);
//		elt++;
//		if ((len -= copy) == 0)
//			return elt;
//		offset += copy;
//	}

//	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
//		int end;

//		WARN_ON(start > offset + len);

//		end = start + skb_frag_size(&skb_shinfo(skb)->frags[i]);
//		if ((copy = end - offset) > 0) {
//			skb_frag_t *frag = &skb_shinfo(skb)->frags[i];

//			if (copy > len)
//				copy = len;
//			sg_set_page(&sg[elt], skb_frag_page(frag), copy,
//					frag->page_offset+offset-start);
//			elt++;
//			if (!(len -= copy))
//				return elt;
//			offset += copy;
//		}
//		start = end;
//	}

//	skb_walk_frags(skb, frag_iter) {
//		int end;

//		WARN_ON(start > offset + len);

//		end = start + frag_iter->len;
//		if ((copy = end - offset) > 0) {
//			if (copy > len)
//				copy = len;
//			elt += __skb_to_sgvec(frag_iter, sg+elt, offset - start,
//					      copy);
//			if ((len -= copy) == 0)
//				return elt;
//			offset += copy;
//		}
//		start = end;
//	}
//	BUG_ON(len);
//	return elt;
//}

//int skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
//{
//	int nsg = __skb_to_sgvec(skb, sg, offset, len);

//	sg_mark_end(&sg[nsg - 1]);

//	return nsg;
//}
////EXPORT_SYMBOL_GPL(skb_to_sgvec);

///**
// *	skb_cow_data - Check that a socket buffer's data buffers are writable
// *	@skb: The socket buffer to check.
// *	@tailbits: Amount of trailing space to be added
// *	@trailer: Returned pointer to the skb where the @tailbits space begins
// *
// *	Make sure that the data buffers attached to a socket buffer are
// *	writable. If they are not, private copies are made of the data buffers
// *	and the socket buffer is set to use these instead.
// *
// *	If @tailbits is given, make sure that there is space to write @tailbits
// *	bytes of data beyond current end of socket buffer.  @trailer will be
// *	set to point to the skb in which this space begins.
// *
// *	The number of scatterlist elements required to completely map the
// *	COW'd and extended socket buffer will be returned.
// */
//int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer)
//{
//	int copyflag;
//	int elt;
//	struct sk_buff *skb1, **skb_p;

//	/* If skb is cloned or its head is paged, reallocate
//	 * head pulling out all the pages (pages are considered not writable
//	 * at the moment even if they are anonymous).
//	 */
//	if ((skb_cloned(skb) || skb_shinfo(skb)->nr_frags) &&
//	    __pskb_pull_tail(skb, skb_pagelen(skb)-skb_headlen(skb)) == NULL)
//		return -ENOMEM;

//	/* Easy case. Most of packets will go this way. */
//	if (!skb_has_frag_list(skb)) {
//		/* A little of trouble, not enough of space for trailer.
//		 * This should not happen, when stack is tuned to generate
//		 * good frames. OK, on miss we reallocate and reserve even more
//		 * space, 128 bytes is fair. */

//		if (skb_tailroom(skb) < tailbits &&
//		    pskb_expand_head(skb, 0, tailbits-skb_tailroom(skb)+128, GFP_ATOMIC))
//			return -ENOMEM;

//		/* Voila! */
//		*trailer = skb;
//		return 1;
//	}

//	/* Misery. We are in troubles, going to mincer fragments... */

//	elt = 1;
//	skb_p = &skb_shinfo(skb)->frag_list;
//	copyflag = 0;

//	while ((skb1 = *skb_p) != NULL) {
//		int ntail = 0;

//		/* The fragment is partially pulled by someone,
//		 * this can happen on input. Copy it and everything
//		 * after it. */

//		if (skb_shared(skb1))
//			copyflag = 1;

//		/* If the skb is the last, worry about trailer. */

//		if (skb1->next == NULL && tailbits) {
//			if (skb_shinfo(skb1)->nr_frags ||
//			    skb_has_frag_list(skb1) ||
//			    skb_tailroom(skb1) < tailbits)
//				ntail = tailbits + 128;
//		}

//		if (copyflag ||
//		    skb_cloned(skb1) ||
//		    ntail ||
//		    skb_shinfo(skb1)->nr_frags ||
//		    skb_has_frag_list(skb1)) {
//			struct sk_buff *skb2;

//			/* Fuck, we are miserable poor guys... */
//			if (ntail == 0)
//				skb2 = skb_copy(skb1, GFP_ATOMIC);
//			else
//				skb2 = skb_copy_expand(skb1,
//						       skb_headroom(skb1),
//						       ntail,
//						       GFP_ATOMIC);
//			if (unlikely(skb2 == NULL))
//				return -ENOMEM;

//			if (skb1->sk)
//				skb_set_owner_w(skb2, skb1->sk);

//			/* Looking around. Are we still alive?
//			 * OK, link new skb, drop old one */

//			skb2->next = skb1->next;
//			*skb_p = skb2;
//			kfree_skb(skb1);
//			skb1 = skb2;
//		}
//		elt++;
//		*trailer = skb1;
//		skb_p = &skb1->next;
//	}

//	return elt;
//}
////EXPORT_SYMBOL_GPL(skb_cow_data);

//static void sock_rmem_free(struct sk_buff *skb)
//{
//	struct sock *sk = skb->sk;

//	atomic_sub(skb->truesize, &sk->sk_rmem_alloc);
//}

///*
// * Note: We dont mem charge error packets (no sk_forward_alloc changes)
// */
//int sock_queue_err_skb(struct sock *sk, struct sk_buff *skb)
//{
//	int len = skb->len;

//	if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
//	    (unsigned)sk->sk_rcvbuf)
//		return -ENOMEM;

//	skb_orphan(skb);
//	skb->sk = sk;
//	skb->destructor = sock_rmem_free;
//	atomic_add(skb->truesize, &sk->sk_rmem_alloc);

//	/* before exiting rcu section, make sure dst is refcounted */
//	skb_dst_force(skb);

//	skb_queue_tail(&sk->sk_error_queue, skb);
//	if (!sock_flag(sk, SOCK_DEAD))
//		sk->sk_data_ready(sk, len);
//	return 0;
//}
//EXPORT_SYMBOL(sock_queue_err_skb);

//void skb_tstamp_tx(struct sk_buff *orig_skb,
//		struct skb_shared_hwtstamps *hwtstamps)
//{
//	struct sock *sk = orig_skb->sk;
//	struct sock_exterr_skb *serr;
//	struct sk_buff *skb;
//	int err;

//	if (!sk)
//		return;

//	skb = skb_clone(orig_skb, GFP_ATOMIC);
//	if (!skb)
//		return;

//	if (hwtstamps) {
//		*skb_hwtstamps(skb) =
//			*hwtstamps;
//	} else {
//		/*
//		 * no hardware time stamps available,
//		 * so keep the shared tx_flags and only
//		 * store software time stamp
//		 */
//		skb->tstamp = ktime_get_real();
//	}

//	serr = SKB_EXT_ERR(skb);
//	memset(serr, 0, sizeof(*serr));
//	serr->ee.ee_errno = ENOMSG;
//	serr->ee.ee_origin = SO_EE_ORIGIN_TIMESTAMPING;

//	err = sock_queue_err_skb(sk, skb);

//	if (err)
//		kfree_skb(skb);
//}
////EXPORT_SYMBOL_GPL(skb_tstamp_tx);


///**
// * skb_partial_csum_set - set up and verify partial csum values for packet
// * @skb: the skb to set
// * @start: the number of bytes after skb->data to start checksumming.
// * @off: the offset from start to place the checksum.
// *
// * For untrusted partially-checksummed packets, we need to make sure the values
// * for skb->csum_start and skb->csum_offset are valid so we don't oops.
// *
// * This function checks and sets those values and skb->ip_summed: if this
// * returns false you should drop the packet.
// */
//bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off)
//{
//	if (unlikely(start > skb_headlen(skb)) ||
//	    unlikely((int)start + off > skb_headlen(skb) - 2)) {
//		if (net_ratelimit())
//			printk(KERN_WARNING
//			       "bad partial csum: csum=%u/%u len=%u\n",
//			       start, off, skb_headlen(skb));
//		return false;
//	}
//	skb->ip_summed = CHECKSUM_PARTIAL;
//	skb->csum_start = skb_headroom(skb) + start;
//	skb->csum_offset = off;
//	return true;
//}
////EXPORT_SYMBOL_GPL(skb_partial_csum_set);

//void __skb_warn_lro_forwarding(const struct sk_buff *skb)
//{
//	if (net_ratelimit())
//		pr_warning("%s: received packets cannot be forwarded"
//			   " while LRO is enabled\n", skb->dev->name);
//}
//EXPORT_SYMBOL(__skb_warn_lro_forwarding);

///**
// * skb_gso_transport_seglen - Return length of individual segments of a gso packet
// *
// * @skb: GSO skb
// *
// * skb_gso_transport_seglen is used to determine the real size of the
// * individual segments, including Layer4 headers (TCP/UDP).
// *
// * The MAC/L2 or network (IP, IPv6) headers are not accounted for.
// */
//unsigned int skb_gso_transport_seglen(const struct sk_buff *skb)
//{
//	const struct skb_shared_info *shinfo = skb_shinfo(skb);

//	if (likely(shinfo->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6)))
//		return tcp_hdrlen(skb) + shinfo->gso_size;

//	/* UFO sets gso_size to the size of the fragmentation
//	 * payload, i.e. the size of the L4 (UDP) header is already
//	 * accounted for.
//	 */
//	return shinfo->gso_size;
//}
////EXPORT_SYMBOL_GPL(skb_gso_transport_seglen);
